Many improvements have been made in the area of hand trucks and dollies for material handling. However, none of these improvements have efficiently and effectively addressed the needs of professional musicians. Professional musicians are required to transport wide varieties of musical instruments and related gear often utilizing small cars and trucks over various terrains and changing environments while travelling to and from performance sites. Due to the virtual explosion in technology over the last ten years regarding P.A. systems, electronic keyboards, effects and the like, musical groups require more equipment than ever before. The problems of transporting the above-mentioned equipment have become increasingly difficult. It is desirable to create a specialized dolly or cart that can satisfy the criteria of musicians.
In the past few years, mini-vans and small trucks have been placed in common use for the transport of musical and other equipment. As such, space limitations have become of great concern to musicians. Any transport carts must now have a size which can carry large loads yet collapse to a small storage size so as to leave maximum room for equipment with the mini-van. Space is at a premium within a mini-van or a small truck.
Initially, it is desirable to produce a lightweight cart weighing under thirty-five pounds. It has been found that professional musicians experience finger stiffening and muscle stiffening in the hands and forearms when lifting objects over forty pounds which is deleterious to musical performance. In addition, the carrying of heavy equipment can contribute to back problems and related physical impairment. In addition, it also tights laryngeal muscles and, thus, hampers singing performance.
When transporting musical equipment, any cart or dolly should be capable of supporting at least five hundred pounds or more. Musical equipment is delicate and should be transported smoothly and without shock. In addition, the musical equipment should be properly supported and handled with care. Any handtruck or dolly must be able to reduce to a size of three feet of length or less with one side flat so as to facilitate receipt in small cars or trucks and/or baggage handling in airports.
In order to effectively accommodate keyboards and large P.A. cabinets, a cart must have the ability to extend to approximately fifty-four inches. It should also be short enough to maneuver through labrinyth-like corridors and elevators, often found in hotels and stage areas. Support should be provided on each end of the cart so as to maintain the expensive and delicate equipment within the confines of the frame of the dolly. Tall foldable sides can be useful for securing equipment such as drums, guitars, horns and the like, as well as acting as a hanger for various stage clothes. Also, the cart should be able to act as a "platform cart" so that the bed of the cart is flat with one side upright so as to accommodate long 24-channel mixing consoles or lighting trusses that would overhang the ends of the cart.
Since the equipment must be transported over various terrains, the cart should have the quality suitable for rolling smoothly and shock-free over such various terrains. The wheeled mechanism of the dolly or cart should be suitable for traversing curbs, stairs, grass, dirt and rough pavement. The cart should provide a broad frame surface so as to easily receive the musical equipment. A non-skid surface is useful in order to prevent odd-shaped instruments and widely-used polyethylene cases (which are notoriously slippery) from slipping and falling off during transport. The cart should be able to be converted from a two-wheel hand truck to a four-wheel cart or any other configuration both extremely quickly and efficiently. Since the cart must be loaded and unloaded often between musical performances, complete assembly into any loading configuration should be completed within ten seconds.
It is often the requirement of musicians that they must set up extremely quickly and must break down the equipment quickly. As such, it is a requirement for a musical instrument transport cart that the cart be able to be assembled into its proper position for receiving equipment very quickly and easily. Undue manipulation of screws, nuts, bolts, and other items wastes a great deal of time and is generally unsuitable for the purposes of the musician. A musical instrument transport cart must be capable of rapid assembly. The cart should also be capable of assuming any configurations within ten seconds or less. The cart should also be able to carry small objects on the frame without falling through.
A caster brake is necessary so as to allow the cart to be retained on uneven surfaces.
It is also important for musical equipment to be maintained on a surface parallel to the surface on which the cart is travelling. As such, the frame of the cart should be supported on wheels which maintain the frame in parallel relationship to the earth. Any angling of the frame will tend to cause the equipment to move to the lowest end of the cart. The angling may also cause excessive and unexpected pressures to be applied to cart components. In order to enhance the ability to maintain the parallelism of the cart to the surface, the handle should be foldable in such a way so as to maintain this parallelism.
Various patents have issued in the past which deal with various types of collapsible hand trucks and dollies. U.S. Pat. No. 1,662,730, issued on Mar. 13, 1928, to Wertenberger et al. shows a stylized truck having a broad surface with suitable caster wheels for transporting bathtubs. U.S. Pat. No. 2,519,113, issued on Aug. 15, 1950, to L. I. Cohn shows a hand truck having a collapsible handle at one end, a stair climbing apparatus, and an adjustable frame. U.S. Pat. No. 2,620,041, issued on Dec. 2, 1952, to Chenette et al. shows a truck having a treaded stair climbing attachment. U.S. Pat. No. 2,820,643, issued on Jan. 21, 1958, to L. I. Cohn shows a hand truck and dolly having an adjustable handle for converting the truck into a dolly. U.S. Pat. No. 3,104,890, issued on Sep. 24, 1963, to N. Hill shows a utility cart having telescoping tubular frame members. U.S. Pat. No. 3,206,790, issued on Sep. 21, 1965, to C. Romay describes a locking assembly for a swiveled caster as used on trucks and other carts. U.S. Pat. No. 3,759,538, issued on Sep. 18, 1973, to A. J. Fabiano illustrates a mobile storage facility having wheels and handles for supporting a tray for garden implements, accessories, and supplies. U.S. Pat. No. 3,761,107, issued on Sep. 25, 1973, to Dochery et al. shows an adjustable dolly for supporting furniture thereon. U.S. Pat. No. 3,837,667, issued on Sep. 24, 1974, to M. A. Sernovitz shows an open-framed cart for receiving containers stacked in a nested relationship. U.S. Pat. No. 4,009,891, issued on Mar. 1, 1977, to O. Jensen provides a hand truck and dolly with an adjustable frame and support chassis. U.S. Pat. No. 4,448,440, issued on May 15, 1984, to R. H. Gier discloses a hand truck having a load supporting platform pivotted to swing from an operative position to a position flush against the frame. U.S. Pat. No. 4,637,626, issued on Jan. 20, 1987, to Foss et al. shows a portable, foldable and convertible luggage trolley. U.S. Pat. No. 4,717,168, issued on Jan. 5, 1988, to J. R. Moon discloses a utility cart having a pair of balloon tire wheels supporting a frame counterbalanced for easy pushing. A pair of caster wheels are provided on the front of the inclined frame. U.S. Pat. No. 4,796,909, issued on Jan. 10, 1989, to V. S. Kirkendall describes a four wheeled pull-type service cart designed to transport heavy loads over sandy terrain. European Patent No. 294,249 shows a dolly having a detachable tubular structure which provides an extendible platform.
U.S. Pat. No. 5,228,716, issued on Jul. 20, 1993, to the present inventor teaches a convertible transport cart. After experimentation with the transport cart of this U.S. patent, it was found that several improvements were possible. First, it was found that the rectangular frame, although strong, lacked a certain degree of structural integrity. Additionally, it was found that the rectangular frame of this patent inhibited the ability to transport certain small articles (i.e., those articles that had a length less than the width between the bars of the frame). Often, musicians would complain that certain small objects could not be conveniently transported by the cart because of the wide spacing between the sides of the frame. Another problem which was noted was when the cart was configured in its "hand truck" position, there were occasions when the telescoping U-shaped members would slide from one another, especially if the thumbnuts were not sufficiently tightened. The lack of a safeguard mechanism to prevent the members from telescoping apart was a concern to certain users of the cart.
It is an object of the present invention to provide a convertible cart designed to be use in combination with the transport of musical equipment.
It is an object to provide a cart that will carry up to five hundred pounds, will extend to fifty-two inches in length, weigh less than thirty-five pounds, and collapse to thirty-six inches in length for storage, be durable, and be relatively inexpensive.
It is another object of the present invention to provide a telescoping and collapsible cart for easy storage.
It is another object of the present invention to provide foldable handles having a sufficient height to allow for efficient stacking and carrying of delicate musical equipment as well as for allowing for easy storage.
It is another object of the present invention to provide a cart that is long enough so that the handle folds flat within the framework of the cart.
It is a further object of the present invention to provide a locking mechanism for the handles of a cart which allows the handles to be positioned up or down within one second each.
It is a further object of the present invention to provide a cart having handles and a frame that can be arranged so as to maintain a parallel relationship with the earth.
It is still a further object of the present invention to provide a cart that can be easily transported through airports and the like by having a folded length of three feet or less and a flat side for airport transport belts.
It is another object to provide a cart that has minimal protrusions for the prevention of snagging, scraping, and injury.
It is another object to provide a cart that will carry smaller objects as well as larger objects without slipping through the frame.
It is another object of the present invention to provide a cart that limits the amount of telescoping movement and for preventing telescoping separation of the cart.
It is a further object of the present invention to provide a cart that is convertible between a platform cart, a piano dolly, a two-wheel or four-wheel hi-stacker, and a storage unit configuration.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.